Air Conditioning and Heating R-12 All Caterpillar Machines – Refrigerant Leakage – Test

Leak Detector

------ WARNING! ------

Personal injury can result from contact with refrigerant.

This system is under pressure at all times, even if the engine is not running. Heat should never be applied to a charged system.

Contact with refrigerant can cause frost bite. Keep face and hands away to help prevent injury.

Protective goggles must always be worn when refrigerant lines are opened, even if the gauges indicate the system is empty of refrigerant.

Always use caution when a fitting is removed. Slowly loosen the fitting. If the system is still under pressure, evacuate the system recovering the refrigerant before removing the fitting.

Personal injury or death can result from inhaling refrigerant through a lit cigarette.

Inhaling air conditioner refrigerant gas through a lit cigarette or other smoking method or inhaling fumes released from a flame contacting air conditioner refrigerant gas, can cause bodily harm or death.

Do not smoke when servicing air conditioners or wherever refrigerant gas may be present.

Before any checks of the air conditioning and heating system are made, move the machine to a smooth horizontal surface. Lower all implements to the ground. Make sure the transmission is in neutral or park and that the parking brake is engaged. Keep all other personnel away from the machine or where they can be seen.


Table 1
Required Tools    
Part Number     Part Description     Qty    
208-1374     Refrigerant Leak Detector     1    

The 208-1374 Refrigerant Leak Detectors are designed in order to detect leaks as small as 7.4 mL (.25 oz) per year of refrigerant in the air conditioning system. Perform the following procedure in order to determine if the system has a leak.

The system must contain at least 345 kPa (50 psi) of pressure. Install the manifold gauge set. The manifold gauge set can determine if pressure exists in the system. A leak test can be performed if the system indicates pressure.

Note: Refrigerant vapor is heavier than air. For best results, place the sensor tip directly below possible leaks.

Note: Leaks in the high pressure side of the system are more easily found if the air conditioner is operated for a few minutes. The leak test must be performed immediately after the unit is turned OFF. The leak test for the high pressure side is performed before the pressures in the system equalize. Leaks in the low pressure side of the system are more easily found if the air conditioner has been turned OFF for several minutes. The leak test for the low pressure side is performed after the pressures in the system equalize.

  1. Move the sensor tip along possible leak points at a rate of one inch per second.
  1. It may not be necessary to recover refrigerant if a loose fitting or a loose connection is causing a leak. Tighten the loose connection and perform the performance check procedure. If necessary, add refrigerant to the air conditioning system. Refer to the Testing and Adjusting, SENR3334, “Refrigerant System – Charge” section for the proper procedure.
  1. If the repair of a leak calls for the removal or the replacement of a component, refer to Disassembly and Assembly, SENR3334.
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